Pentax KP vs Nikon D40

The Pentax KP and the Nikon D40 are two digital cameras that were announced, respectively, in January 2017 and November 2006. Both are DSLR (Digital Single Lens Reflex) cameras that are equipped with an APS-C sensor. The Pentax has a resolution of 24.1 megapixels, whereas the Nikon provides 6 MP.

Below is an overview of the main specs of the two cameras as a starting point for the comparison.

Headline Specifications

Pentax KP		Nikon D40
Digital single lens reflex		Digital single lens reflex
Pentax K mount lenses		Nikon F mount lenses
24.1 MP – APS-C sensor		6 MP – APS-C sensor
1080/60i Video		no Video
ISO 100-819,200		ISO 200-1,600 (200 - 3,200)
Optical viewfinder		Optical viewfinder
3.0" LCD – 921k dots		2.5" LCD – 230k dots
Tilting screen (no touchscreen)		Fixed screen (not touch-sensitive)
7 shutter flaps per second		2.5 shutter flaps per second
In-body stabilization		Lens stabilization only
Weathersealed body		not weather sealed
390 shots per battery charge		470 shots per battery charge
132 x 101 x 76 mm, 703 g		124 x 94 x 64 mm, 522 g

Check KP offers at
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Check D40 offers at
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Going beyond this snapshot of core features and characteristics, what are the differences between the Pentax KP and the Nikon D40? Which one should you buy? Read on to find out how these two cameras compare with respect to their body size, their imaging sensors, their shooting features, their input-output connections, and their reception by expert reviewers.

Body comparison

An illustration of the physical size and weight of the Pentax KP and the Nikon D40 is provided in the side-by-side display below. The two cameras are presented according to their relative size. Three consecutive perspectives from the front, the top, and the back are available. All width, height and depth measures are rounded to the nearest millimeter.

The KP can be obtained in two different colors (black, silver), while the D40 is only available in black.

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Nikon D40 is notably smaller (13 percent) than the Pentax KP. Moreover, the D40 is markedly lighter (26 percent) than the KP. It is worth mentioning in this context that the KP is splash and dust resistant, while the D40 does not feature any corresponding weather-sealing.

The above size and weight comparisons are to some extent incomplete since they do not consider the interchangeable lenses that both of these cameras require. Hence, you might want to study and compare the specifications of available lenses in order to get the full picture of the size and weight of the two camera systems.

Concerning battery life, the KP gets 390 shots out of its Pentax D-LI109 battery, while the D40 can take 470 images on a single charge of its Nikon EN-EL9 power pack.

The adjacent table lists the principal physical characteristics of the two cameras alongside a wider set of alternatives. If you would like to visualize and compare a different camera combination, you can navigate to the CAM-parator app and make your selection from a broad list of cameras there.

Body Specifications

		Camera Model	Camera Width	Camera Height	Camera Depth	Camera Weight	Battery Life	Weather Sealing	Camera Launch	Launch Price (USD)	Street Price
1.		Pentax KP	132 mm	101 mm	76 mm	703 g	390	Y	Jan 2017	1,099	ebay.com
2.		Nikon D40	124 mm	94 mm	64 mm	522 g	470	n	Nov 2006	499	ebay.com
3.		Fujifilm X-H1	140 mm	97 mm	86 mm	673 g	310	Y	Feb 2018	1,899	ebay.com
4.		Nikon D40X	124 mm	94 mm	64 mm	522 g	520	n	Mar 2007	729	ebay.com
5.		Nikon D50	133 mm	102 mm	76 mm	620 g	400	n	Apr 2005	749	ebay.com
6.		Nikon D3100	124 mm	96 mm	75 mm	505 g	550	n	Aug 2010	599	ebay.com
7.		Nikon D3300	124 mm	98 mm	76 mm	430 g	700	n	Jan 2014	499	ebay.com
8.		Nikon D3400	124 mm	98 mm	76 mm	445 g	1200	n	Aug 2016	499	ebay.com
9.		Nikon D7500	136 mm	104 mm	73 mm	720 g	950	Y	Apr 2017	1,299	amazon.com
10.		Pentax K-3	131 mm	100 mm	77 mm	800 g	560	Y	Oct 2013	1,299	ebay.com
11.		Pentax K-3 II	131 mm	100 mm	77 mm	800 g	720	Y	Apr 2015	1,099	ebay.com
12.		Pentax K-3 III	135 mm	104 mm	74 mm	820 g	800	Y	Mar 2021	1,999	amazon.com
13.		Pentax K-5	131 mm	97 mm	73 mm	760 g	740	Y	Sep 2010	1,099	ebay.com
14.		Pentax K-5 II	131 mm	97 mm	73 mm	760 g	740	Y	Sep 2012	1,099	ebay.com
15.		Pentax K-70	126 mm	93 mm	74 mm	688 g	410	Y	Jun 2016	649	ebay.com
16.		Pentax K-S2	123 mm	91 mm	73 mm	678 g	410	Y	Feb 2015	749	ebay.com
17.		Sony A77 II	143 mm	104 mm	81 mm	647 g	480	Y	May 2014	1,199	ebay.com
Note: Measurements and pricing do not include easily detachable parts, such as add-on or interchangeable lenses or optional viewfinders.
Convert to Imperial

The price is, of course, an important factor in any camera decision. The listed launch prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The D40 was launched at a markedly lower price (by 55 percent) than the KP, which puts it into a different market segment. Usually, retail prices stay at first close to the launch price, but after several months, discounts become available. Later in the product cycle and, in particular, when the replacement model is about to appear, further discounting and stock clearance sales often push the camera price considerably down. Then, after the new model is out, very good deals can frequently be found on the pre-owned market.

Sensor comparison

The imaging sensor is at the core of digital cameras and its size is one of the main determining factors of image quality. A large sensor will tend to have larger individual pixels that provide better low-light sensitivity, wider dynamic range, and richer color-depth than smaller pixel-units in a sensor of the same technological generation. Further, a large sensor camera will give the photographer additional creative options when using shallow depth-of-field to isolate a subject from its background. On the downside, larger sensors are more costly to manufacture and tend to lead to bigger and heavier cameras and lenses.

Both cameras under consideration feature an APS-C sensor, but their sensors differ slightly in size. The sensor area in the D40 is 1 percent bigger. They nevertheless have the same format factor of 1.5. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.

Despite having a slightly smaller sensor, the Pentax KP offers a higher resolution of 24.1 megapixels, compared with 6 MP of the Nikon D40. This megapixels advantage comes at the cost of a higher pixel density and a smaller size of the individual pixel (with a pixel pitch of 3.90μm versus 7.85μm for the D40). However, it should be noted that the KP is much more recent (by 10 years and 2 months) than the D40, and its sensor will have benefitted from technological advances during this time that make it possible to gather light more efficiently. Coming back to sensor resolution, it should be mentioned that the KP has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.

The resolution advantage of the Pentax KP implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the KP for good quality output (200 dots per inch) amounts to 30.1 x 20 inches or 76.4 x 50.8 cm, for very good quality (250 dpi) 24.1 x 16 inches or 61.1 x 40.6 cm, and for excellent quality (300 dpi) 20.1 x 13.3 inches or 50.9 x 33.9 cm. The corresponding values for the Nikon D40 are 15 x 10 inches or 38.2 x 25.4 cm for good quality, 12 x 8 inches or 30.6 x 20.3 cm for very good quality, and 10 x 6.7 inches or 25.5 x 16.9 cm for excellent quality prints.

Unlike the D40, the KP has the capacity to capture high quality composite images by combining multiple shots after shifting its sensor by miniscule distances. This multi-shot, pixel-shift mode is most suitable for photography of stationary objects (landscapes, studio scenes).

The Pentax KP has a native sensitivity range from ISO 100 to ISO 819200. The corresponding ISO settings for the Nikon D40 are ISO 200 to ISO 1600, with the possibility to increase the ISO range to 200-3200.

In terms of underlying technology, the KP is build around a CMOS sensor, while the D40 uses a CCD imager. Both cameras use a Bayer filter for capturing RGB colors on a square grid of photosensors. This arrangement is found in most digital cameras.

For many cameras, data on sensor performance has been reported by DXO Mark. This service determines an overall sensor rating, as well as sub-scores for low-light sensitivity ("DXO Sports"), dynamic range ("DXO Landscape"), and color depth ("DXO Portrait"). The following table provides an overview of the physical sensor characteristics, as well as the sensor quality measurements for a selection of comparators.

Sensor Characteristics

		Camera Model	Sensor Class	Resolution (MP)	Horiz. Pixels	Vert. Pixels	Video Format	DXO Portrait	DXO Landscape	DXO Sports	DXO Overall
1.		Pentax KP	APS-C	24.1	6016	4000	1080/60i	23.9	13.2	1699	81
2.		Nikon D40	APS-C	6.0	3008	2000	none	21.0	11.0	561	56
3.		Fujifilm X-H1	APS-C	24.0	6000	4000	4K/30p	24.0	13.3	1806	82
4.		Nikon D40X	APS-C	10.0	3872	2592	none	22.4	11.4	516	63
5.		Nikon D50	APS-C	6.0	3008	2000	none	20.9	10.8	560	55
6.		Nikon D3100	APS-C	14.2	4608	3072	1080/24p	22.5	11.3	919	67
7.		Nikon D3300	APS-C	24.0	6000	4000	1080/60p	24.3	12.8	1385	82
8.		Nikon D3400	APS-C	24.0	6000	4000	1080/60p	24.8	13.9	1192	86
9.		Nikon D7500	APS-C	20.7	5568	3712	4K/30p	24.3	14.0	1483	86
10.		Pentax K-3	APS-C	24.1	6016	4000	1080/60i	23.7	13.4	1216	80
11.		Pentax K-3 II	APS-C	24.1	6016	4000	1080/60i	23.6	13.6	1106	80
12.		Pentax K-3 III	APS-C	25.6	6192	4128	4K/30p	24.2	13.7	2083	85
13.		Pentax K-5	APS-C	16.1	4928	3264	1080/25p	23.7	14.1	1162	82
14.		Pentax K-5 II	APS-C	16.1	4928	3264	1080/25p	23.8	14.1	1235	82
15.		Pentax K-70	APS-C	24.0	6000	4000	1080/60i	23.8	13.1	1639	80
16.		Pentax K-S2	APS-C	20.0	5472	3648	1080/30p	23.6	12.9	1514	79
17.		Sony A77 II	APS-C	24.0	6000	4000	1080/60p	24.4	13.4	1013	82
Note: DXO values in italics represent estimates based on sensor size and age.

Many modern cameras cannot only take still pictures, but also record videos. The KP indeed provides movie recording capabilities, while the D40 does not. The highest resolution format that the KP can use is 1080/60i.

Feature comparison

Beyond body and sensor, cameras can and do differ across a range of features. The KP and the D40 are similar in the sense that both have an optical viewfinder. The latter is useful for getting a clear image for framing even in brightly lit environments. The viewfinder in the KP offers a wider field of view (100%) than the one in the D40 (95%), so that a larger proportion of the captured image is visible in the finder. In addition, the viewfinder of the KP has a higher magnification (0.63x vs 0.53x), so that the size of the image transmitted appears closer to the size seen with the naked human eye. The table below summarizes some of the other core capabilities of the Pentax KP and Nikon D40 in connection with corresponding information for a sample of similar cameras.

Core Features

		Camera Model	Viewfinder (Type or 000 dots)	Control Panel (yes/no)	LCD Specifications (inch/000 dots)	LCD Attach- ment	Touch Screen (yes/no)	Max Shutter Speed *	Max Shutter Flaps *	Built-in Flash (yes/no)	Built-in Image Stab
1.		Pentax KP	optical	n	3.0 / 921	tilting	n	1/6000s	7.0/s	Y	Y
2.		Nikon D40	optical	n	2.5 / 230	fixed	n	1/4000s	2.5/s	Y	n
3.		Fujifilm X-H1	3690	Y	3.0 / 1040	full-flex	Y	1/8000s	14.0/s	n	Y
4.		Nikon D40X	optical	n	2.5 / 230	fixed	n	1/4000s	3.0/s	Y	n
5.		Nikon D50	optical	n	2.0 / 130	fixed	n	1/4000s	2.5/s	Y	n
6.		Nikon D3100	optical	n	3.0 / 230	fixed	n	1/4000s	3.0/s	Y	n
7.		Nikon D3300	optical	n	3.0 / 921	fixed	n	1/4000s	5.0/s	Y	n
8.		Nikon D3400	optical	n	3.0 / 921	fixed	n	1/4000s	5.0/s	Y	n
9.		Nikon D7500	optical	Y	3.2 / 922	tilting	Y	1/8000s	8.0/s	Y	n
10.		Pentax K-3	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	Y	Y
11.		Pentax K-3 II	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	n	Y
12.		Pentax K-3 III	optical	Y	3.2 / 1620	fixed	Y	1/8000s	12.0/s	n	Y
13.		Pentax K-5	optical	Y	3.0 / 921	fixed	n	1/8000s	7.0/s	Y	Y
14.		Pentax K-5 II	optical	Y	3.0 / 921	fixed	n	1/8000s	7.0/s	Y	Y
15.		Pentax K-70	optical	n	3.0 / 921	swivel	n	1/6000s	6.0/s	Y	Y
16.		Pentax K-S2	optical	n	3.0 / 921	swivel	n	1/6000s	5.4/s	Y	Y
17.		Sony A77 II	2359	Y	3.0 / 1229	full-flex	n	1/8000s	12.0/s	Y	Y
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

One feature that differentiates the KP and the D40 is in-body image stabilization (IBIS). The KP reduces the risk of handshake-induced blur with all attached lenses, while the D40 offers no blur reduction with lenses that themselves do not provide optical image stabilization.

The reported shutter speed information refers to the use of the mechanical shutter. Yet, some cameras only have an electronic shutter, while others have an electronic shutter in addition to a mechanical one. In fact, the KP is one of those camera that have an additional electronic shutter, which makes completely silent shooting possible. However, this mode is less suitable for photographing moving objects (risk of rolling shutter) or shooting under artificial light sources (risk of flickering).

The Pentax KP has an intervalometer built-in. This enables the photographer to capture time lapse sequences, such as flower blooming, a sunset or moon rise, without purchasing an external camera trigger and related software.

The KP writes its imaging data to SDXC cards, while the D40 uses SDHC cards. The KP supports UHS-I cards (Ultra High Speed data transfer of up to 104 MB/s), while the D40 cannot take advantage of Ultra High Speed SD cards.

Connectivity comparison

For some imaging applications, the extent to which a camera can communicate with its environment can be an important aspect in the camera decision process. The table below provides an overview of the connectivity of the Pentax KP and Nikon D40 and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.

Input-Output Connections

		Camera Model	Hotshoe Port	Internal Mic / Speaker	Microphone Port	Headphone Port	HDMI Port	USB Port	WiFi Support	NFC Support	Bluetooth Support
1.		Pentax KP	Y	stereo / mono	Y	-	-	2.0	Y	-	-
2.		Nikon D40	Y	- / -	-	-	-	2.0	-	-	-
3.		Fujifilm X-H1	Y	stereo / mono	Y	-	micro	3.0	Y	-	-
4.		Nikon D40X	Y	- / -	-	-	-	2.0	-	-	-
5.		Nikon D50	Y	- / -	-	-	-	2.0	-	-	-
6.		Nikon D3100	Y	mono / mono	-	-	mini	2.0	-	-	-
7.		Nikon D3300	Y	mono / mono	Y	-	mini	2.0	-	-	-
8.		Nikon D3400	Y	mono / mono	-	-	mini	2.0	-	-	Y
9.		Nikon D7500	Y	stereo / mono	Y	Y	mini	2.0	Y	-	Y
10.		Pentax K-3	Y	mono / mono	Y	Y	mini	3.0	-	-	-
11.		Pentax K-3 II	Y	mono / mono	Y	Y	mini	3.0	-	-	-
12.		Pentax K-3 III	Y	stereo / mono	Y	Y	micro	3.2	Y	-	Y
13.		Pentax K-5	Y	stereo / mono	Y	-	mini	2.0	-	-	-
14.		Pentax K-5 II	Y	stereo / mono	Y	-	mini	2.0	-	-	-
15.		Pentax K-70	Y	stereo / mono	Y	-	mini	2.0	Y	-	-
16.		Pentax K-S2	Y	mono / mono	Y	-	micro	2.0	Y	Y	-
17.		Sony A77 II	Y	stereo / mono	Y	-	mini	2.0	Y	Y	-

It is notable that the KP offers wifi support, while the D40 does not. Wifi can be a very convenient means to transfer image data to an off-camera location.

Both the KP and the D40 have been discontinued, but can regularly be found used on ebay. The D40 was replaced by the Nikon D40X, while the KP does not have a direct successor. Further information on the features and operation of the KP and D40 can be found, respectively, in the Pentax KP Manual (free pdf) or the online Nikon D40 Manual.

Review summary

So what conclusions can be drawn? Is the Pentax KP better than the Nikon D40 or vice versa? Below is a summary of the relative strengths of each of the two contestants.

Advantages of the Pentax KP:

• More detail: Offers more megapixels (24.1 vs 6MP) with a 100% higher linear resolution.
• Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
• High quality composites: Can combine several shots after pixel-shifting its sensor.
• Broader imaging potential: Can record not only still images but also 1080/60i movies.
• More complete view: Has a viewfinder with a larger field of view (100% vs 95%).
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.63x vs 0.53x).
• Larger screen: Has a bigger rear LCD (3.0" vs 2.5") for image review and settings control.
• More detailed LCD: Has a higher resolution rear screen (921k vs 230k dots).
• More flexible LCD: Has a tilting screen for odd-angle shots in landscape orientation.
• Faster shutter: Has higher mechanical shutter speed (1/6000s vs 1/4000s) to freeze action.
• Faster burst: Shoots at higher frequency (7 vs 2.5 flaps/sec) to capture the decisive moment.
• Less disturbing: Has an electronic shutter option for completely silent shooting.
• Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
• Better sealing: Is weather sealed to enable shooting in dusty or wet environments.
• Sharper images: Has hand-shake reducing image stabilization built-in.
• Easier file upload: Has wifi built in for automatic backup or image transfer to the web.
• Faster buffer clearing: Has an SD card interface that supports the UHS-I standard.
• More modern: Reflects 10 years and 2 months of technical progress since the D40 launch.

Reasons to prefer the Nikon D40:

• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• More compact: Is smaller (124x94mm vs 132x101mm) and will fit more readily into a bag.
• Less heavy: Has a lower weight (by 181g or 26 percent) and is thus easier to take along.
• Longer lasting: Gets more shots (470 versus 390) out of a single battery charge.
• More affordable: Was introduced into a lower priced category (55 percent cheaper at launch).
• More heavily discounted: Has been around for much longer (launched in November 2006).

If the count of relative strengths (bullet points above) is taken as a measure, the KP is the clear winner of the match-up (18 : 6 points). However, the relative importance of the various individual camera aspects will vary according to personal preferences and needs, so that you might like to apply corresponding weights to the particular features before making a decision on a new camera. A professional wedding photographer will view the differences between cameras in a way that diverges from the perspective of a travel photog, and a person interested in cityscapes has distinct needs from a macro shooter. Hence, the decision which camera is best and worth buying is often a very personal one.

How about other alternatives? Do the specifications of the Pentax KP and the Nikon D40 place the cameras among the top in their class? Find out in the latest Best DSLR Camera listing whether the two cameras rank among the cream of the crop.

In any case, while the comparison of the spec-sheets of cameras can offer a general idea of their imaging potential, it remains partial and cannot reveal, for example, the shooting experience and imaging performance when actually working with the KP or the D40. At times, user reviews, such as those published at amazon, address these issues in a useful manner, but such feedback is on many occasions incomplete, inconsistent, and unreliable.

Expert reviews

This is why expert reviews are important. The adjacent summary-table relays the overall verdicts of several of the most popular camera review sites (amateurphotographer [AP], cameralabs [CL], digitalcameraworld [DCW], dpreview [DPR], ephotozine [EPZ], photographyblog [PB]). As can be seen, the professional reviewers agree in many cases on the quality of different cameras, but sometimes their assessments diverge, reinforcing the earlier point that a camera decision is often a very personal choice.

Expert Camera Reviews

		Camera   Model	AP   score	CL   score	DCW   score	DPR   score	EPZ   score	PB   score	Camera Launch	Launch Price (USD)	Street Price
1.		Pentax KP	4/5	..	3/5	82/100	5/5	4.5/5	Jan 2017	1,099	ebay.com
2.		Nikon D40	..	81/100	..	+ +	o	4.5/5	Nov 2006	499	ebay.com
3.		Fujifilm X-H1	..	+	5/5	86/100	4.5/5	4.5/5	Feb 2018	1,899	ebay.com
4.		Nikon D40X	..	79/100	..	+ +	4/5	4/5	Mar 2007	729	ebay.com
5.		Nikon D50	..	78/100	..	+ +	4/5	4.5/5	Apr 2005	749	ebay.com
6.		Nikon D3100	5/5	+ +	..	72/100	4.5/5	4.5/5	Aug 2010	599	ebay.com
7.		Nikon D3300	3/5	+	..	77/100	4.5/5	4.5/5	Jan 2014	499	ebay.com
8.		Nikon D3400	4/5	+	4/5	76/100	4/5	4.5/5	Aug 2016	499	ebay.com
9.		Nikon D7500	4.5/5	+ +	4.5/5	86/100	5/5	4.5/5	Apr 2017	1,299	amazon.com
10.		Pentax K-3	4/5	..	..	83/100	5/5	5/5	Oct 2013	1,299	ebay.com
11.		Pentax K-3 II	4.5/5	..	..	..	5/5	5/5	Apr 2015	1,099	ebay.com
12.		Pentax K-3 III	4/5	..	3/5	..	4.5/5	..	Mar 2021	1,999	amazon.com
13.		Pentax K-5	4/5	..	..	83/100	5/5	4.5/5	Sep 2010	1,099	ebay.com
14.		Pentax K-5 II	5/5	..	..	80/100	5/5	4.5/5	Sep 2012	1,099	ebay.com
15.		Pentax K-70	4.5/5	..	4/5	79/100	4.5/5	4.5/5	Jun 2016	649	ebay.com
16.		Pentax K-S2	4.5/5	..	..	..	5/5	4.5/5	Feb 2015	749	ebay.com
17.		Sony A77 II	4/5	..	..	80/100	4.5/5	5/5	May 2014	1,199	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

Care should be taken when interpreting the review scores above, though. The assessments were made in relation to similar cameras of the same technological generation. Thus, a score needs to be put into the context of the launch date and the launch price of the camera, and comparing ratings of very distinct cameras or ones that are far apart in terms of their release date have little meaning. Also, please note that some of the review sites have changed their methodology and reporting over time.

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Other camera comparisons

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